Cardboard packaging of this kind, intended for packing objects which are sensitive to impacts, for example bumpers for motor vehicles, produced from a single cardboard blank provided with folding and cutting lines, is known in a number of designs and therefore belongs to the prior art simply on account of public prior use.
Cardboard packaging of this kind is characterized in particular in that said packaging approximates the curved or bent contour of the object. In comparison, simple rectangular cardboard packaging is ruled out for practical use simply for reasons of efficiency. Rather, attempts are being made to keep as small as possible the space inside the cardboard packaging which is not filled by the object in order to reduce transport costs.
In this case, the specific demands placed on the cardboard packaging and the blank thereof arise from the desired concave and convex upper face and lower face respectively, which can also be referred to as a U-shape for example. Of course, in this case the limbs are not necessarily designed so as to be parallel or axisymmetric, with the result that, depending on the purpose of use, various cardboard packaging having correspondingly different complexities are used for different shapes and sizes.
At the same time, however, simple handling of the flat cardboard blank is also required in order for it to be possible to keep the time required for assembling the cardboard packaging within reasonable limits. The same also applies to the degree of difficulty and to the additional staff and means required for assembling the cardboard packaging.
In order to bring the side portions, which form limbs which are inclined relative to the central portion, into the desired position and to correspondingly fix said side portions, the substantially rectangular side portions form, in the bent position in particular maintained by the assembler, an overlap region on the front face and on the rear face respectively. In the overlap region, the side portions are provided with corresponding tuck-in flap connections, which engage in corresponding perforations in the front face and the rear face of the central portion.
In this case, however, the unfavorable leverage ratios, due to which the tuck-in flap connections are heavily loaded even when a relatively low force acts on the upper face of the cardboard packaging, have been found to be disadvantageous. Consequently, the tuck-in flap connections break in this region.
Furthermore, it has been found to be disadvantageous that the opposing tuck-in flaps on the front face and the rear face have to be positioned simultaneously and practical handling is made more difficult thereby. The actual position on the front face and the rear face can often not be controlled or adjusted by one person alone, meaning that, in practice, an additional person is required for assembling the cardboard packaging.
DE 202 08 522 U1 relates to packaging for motor vehicle bumpers, wherein a supporting body carrying the motor vehicle bumper consists of a blank formed in one piece from corrugated cardboard or solid board. An upper and a lower carrying band are interconnected at the ends thereof by means of a connecting web and a connecting tab respectively.
Packaging for motor vehicle bumpers is also known from JP 2007-050920 A, JP 2001-341737 A and JP 06-321231 A.
Moreover, DE 41 00 251 A1 discloses a highly complex collapsible box formed of a single cardboard blank, by which box the object is held in such a way that the use of foam for packing the goods can be dispensed with.